C ++不將數據的第一行插入輸出文件

Question

我是C ++的新手，一直在努力獲取數據文件並讀取它，然后對該數據進行一些數學運算，然后將其全部導出到輸出文件中。 但是我的問題是，每次運行它都會跳過將第一行寫入輸出文件的過程。

我的數據文件是：

Jon Doe 15 7.25
Nick Delgado 8 7.25
Jo Barnes 4 7.25
Harold Griffith 45 11.00
Linda Holmes 30 10.00

我的輸出如下所示：

Nick Delgado 8 7.25 58 0 58
Jo Barnes 4 7.25 29 0 29
Harold Griffith 45 11 522.5 146.3 376.2
Linda Holmes 30 10 300 84 216

它完全跳過了寫有關喬恩·多伊的任何信息。 這是：

Jon Doe 15 7.25 108.75 0 108.75

我嘗試了多種不同的想法，問我的朋友，總的來說，我感到非常沮喪。

我認為問題代碼在這里的某個地方：

    if (!dataOutFile.is_open()) {
        cout << "Couldn't open file";
    }
    else {
        dataOutFile << firstName << " " << lastName << " " << hoursWorked << " " << payRate << " " << grossPay << " " << withHolding << " " << takeHomePay << endl;
        cout << "What was wrote to file: \n" << firstName << " " << lastName << " " << hoursWorked << " " << payRate << " " << grossPay << " " << withHolding << " " << takeHomePay << endl;
    }

因為我的輸出窗口如下所示：

因此，這告訴我的是，它正在到達代碼寫入文件的位置，因為它正在寫入第一個條目之后的其他四個條目。 但是，根據輸出窗口，它正在將文件應有的信息寫入文件，但是由於某種原因，它不是。 我正在使用append命令，因此它不應覆蓋任何內容，根據輸出文件，它不是，而是第一行。

沒有錯誤或警告，並且我的調試日志中沒有錯誤。 請幫助我，任何幫助表示贊賞。 我也意識到代碼有點混亂，我需要將其分解為更多的功能，但是我只是想使其正常工作，然后我才能對其進行清理。

下面是我處理所有這些程序的完整代碼，以防有人需要查看。

#include "stdafx.h"
#include <iostream>
#include <fstream>
#include <string>

using namespace std;

// Global Variables
string fileName;
double totalGrossPay = 0;
double totalWithHolding = 0;
double totalTakeHomePay = 0;
double withHoldingLimit = 200;
double withHoldingRate = .28;
double overtimeRate = 1.5;

// Initialize Functions
void readFile();

int main() {
    cout << "What is the name of your file?" << endl;
    getline(cin, fileName);
    readFile();
}

void readFile() {
    // Variables
    string firstName;
    string lastName;
    double hoursWorked;
    double payRate;
    double grossPay;
    double withHolding;
    double takeHomePay;
    double overtime;
    string dataOutFileName = "Salary.out";

    // Intialize and Open Input File
    ifstream file;
    file.open(fileName);
    // Initialize Output File
    ofstream dataOutFile(dataOutFileName);

    // Check to see if file failed to open
    if (!file.is_open()) return;

    // Define variables needed in the while loop.
    string word;
    int i = 1;

    // Actually reads through the file and prints out what the file has.
    while (i != 0) {
        // Pull up the next word in the word file
        file >> word;
        // Firstname
        if (((i - 1) % 4) == 0) {
            firstName = word;
            cout << "First name: " << firstName << "\n";
        }
        // Last name
        else if (((i - 1) % 4) == 1) {
            lastName = word;
            cout << "Last name: " << lastName << "\n";
        }
        // Hours Worked
        else if (((i - 1) % 4) == 2) {
            hoursWorked = atof(word.c_str());
            cout << "Hours Worked: " << hoursWorked << "\n";
        }
        // Pay Rate
        else if (((i - 1) % 4) == 3) {
            payRate = atof(word.c_str());
            cout << "Pay Rate: " << payRate << "\n";
        }
        // Add 1 to i
        i++;
        // If i-1 divides into 4 with no remainder, move to new line
        // Also since we now have all four variables filled in we can do our math
        if (i > 3 && ((i - 1) % 4) == 0) {
            // Gross Pay
            if (hoursWorked > 40) {
                overtime = hoursWorked - 40;
            }
            else {
                overtime = 0;
            }
            if (overtime != 0) {
                grossPay = (40 * payRate) + (overtime * (payRate * overtimeRate));
            }
            else {
                grossPay = hoursWorked * payRate;
            }
            // Withholding
            if (grossPay > withHoldingLimit) {
                withHolding = grossPay * withHoldingRate;
            }
            else {
                withHolding = 0;
            }
            // Take Home pay
            takeHomePay = grossPay - withHolding;
            // Add to totals
            totalGrossPay += grossPay;
            totalWithHolding += withHolding;
            totalTakeHomePay += takeHomePay;
            // Write to file, and print the line so we know it worked!
            dataOutFile.open(dataOutFileName, fstream::app);
            // Check it if is open
            if (!dataOutFile.is_open()) {
                cout << "Couldn't open file";
            }
            else {
                dataOutFile << firstName << " " << lastName << " " << hoursWorked << " " << payRate << " " << grossPay << " " << withHolding << " " << takeHomePay << endl;
                cout << "What was wrote to file: \n" << firstName << " " << lastName << " " << hoursWorked << " " << payRate << " " << grossPay << " " << withHolding << " " << takeHomePay << endl;
            }
            dataOutFile.close();
            // move to new line
            cout << "\n";
        }
        // Check to see if were at the end of the file, if so end while.
        if (file.eof()) {
            i = 0;
        }
    }
    file.close();
}

Answer 1

基於i的狀態機太復雜了，這里完全不需要。 不要修復它，把它扔掉。

如果您需要閱讀四件事，請一次閱讀四件事。 在while條件下進行。

 ifstream file(filename);
 ofstream dataOutFile(dataOutFileName);

 while (file >> firstName >> lastName >> hoursWorked >> payRate)
 {
      // you have all four pieces of data
      // calculate and print what you need here
 }

不要在循環內調用close()或檢查eof() 。